The proposed research is an extension of our previous studies which have indicated that maternal factors govern normal fetal and neonatal development. Using biochemical, pharmacologic and morphologic techniques we have found that trans-placental influences regulate maturation of the fetal nervous system: bilateral sialectomy (salivary gland removal) of pregnant rats prevents the normal development of the fetal sympathetic nervous system. Moreover, sialectomy of nursing mothers also prevents normal sympathetic ontogeny in the neonates. The present studies will focus on the maternal molecular messages regulating fetal and neonatal growth. More specifically, we hope to a) define the maternal salivary factor(s) which regulate fetal sympathetic ontogeny; b) determine whether these factors cross the placenta; c) determine whether these factors are transmitted to neonates by nursing mothers; d) define the scope of maternal regulation of neuronal development by examining neurotransmitter enzymes; e) define the role of nerve growth factor in maternal regulation of development; f) define new pharmacologic approaches to the treatment of abnormal maternal-infant relations; and g) examine effects of prenatal drug exposure on fetal and neonatal ontogeny.